Red fluorescent glass, preparation method thereof and application of red fluorescent glass in high-power laser display

Abstract

The invention discloses red fluorescent glass as well as a preparation method and application thereof in high-power laser display, and belongs to the technical field of laser display. The red fluorescent glass film is prepared by selecting specific components of the glass matrix and regulating and controlling the proportion of the components, mixing the CaAlSiN3: Eu < 2 + > fluorescent powder with the glass matrix powder and preparing at a relatively low sintering temperature, and the fluorescent glass film prepared by the invention has excellent compactness, effectively improves the external quantum efficiency of the fluorescent powder, and has a good application prospect. And the fluorescence energy conversion efficiency is obviously improved. In addition, the prepared red fluorescent glass film has high thermal conductivity, shows excellent thermal stability and optical performance, effectively avoids the thermal quenching phenomenon, and improves the reliability of long-term use.

Description

Technical Field

[0001] The present invention relates to the technical field of laser display, and in particular to a red fluorescent glass and a preparation method thereof, and an application thereof in high-power laser display. Background Art

[0002] With the rapid development of laser display and laser lighting technologies, the application of fluorescent conversion materials based on solid-state lighting has become an important direction for the new generation of high-brightness display systems and lighting equipment. Among them, the research on green and yellow fluorescent materials has made significant progress, and their performance under high-power laser excitation can already meet the needs of industrial applications. However, compared with green and yellow fluorescent materials, the research on red fluorescent materials still faces many technical limitations. In particular, under the condition of high laser power density excitation, red fluorescent materials usually have bottleneck problems such as low quantum efficiency, poor thermal stability, light saturation effect and fluorescence thermal quenching, which greatly restricts their application in the field of high-brightness laser display and lighting. In particular, bulk ceramic materials have performance bottlenecks such as difficult synthesis, size limitations, poor thermal radiation resistance, and fluorescence thermal quenching, making them unsuitable for large-scale production.

[0003] Fluorescent glass film is a kind of all-inorganic light conversion material obtained by coating phosphor powder and matrix glass powder into a paste on a high thermal conductivity substrate through doctor blade coating or screen printing. It has the excellent luminous properties of phosphor powder and also has high thermal conductivity and heat aging resistance. However, for red nitride phosphors (such as CaAlSiN3:Eu 2+ Because these phosphors are susceptible to thermal corrosion at high temperatures, there is currently no suitable low-melting-point glass material that can be co-fired with them. During the co-firing process, both the matrix glass and the heat treatment temperature affect the phosphor's luminescence properties, while maintaining film density is difficult, thus limiting its application in fluorescent conversion materials. Summary of the Invention

[0004] In order to solve the above problems in the prior art, the primary purpose of the present invention is to provide a red fluorescent glass film.

[0005] Another object of the present invention is to provide a phosphor.

[0006] Another object of the present invention is to provide an application of the above-mentioned red fluorescent glass film or the above-mentioned phosphor in a high-power reflective laser display.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A red fluorescent glass film, comprising a glass matrix and CaAlSiN3:Eu 2+Phosphor and thermally conductive substrate, the glass matrix comprises the following raw materials in percentage by weight: SiO2 20-40wt%, B2O3 10-30wt%, ZnO 30-50wt%, Al2O3 1-5wt%, K2CO3 4-10wt%, Na2O 5-10wt%, CaO 1-4wt%, BaO 2-5wt%, MgO 1-4wt%;

[0009] The phosphor accounts for 20% to 50wt% of the total mass of the glass matrix and the phosphor. The preparation method of the red fluorescent glass film includes: first calcining the above raw materials to obtain a glass matrix powder, then mixing the glass matrix powder with the phosphor and applying it on a substrate, and sintering to obtain a red fluorescent glass film; the sintering temperature is 500 to 700°C.

[0010] Preferably, the sintering temperature is 570-620°C.

[0011] More preferably, the sintering temperature is 600°C.

[0012] Preferably, the phosphor accounts for 40% to 50 wt% of the total mass of the glass matrix and the phosphor.

[0013] Preferably, the glass matrix includes the following raw materials in mass percentage: SiO2 26-28wt%, B2O3 17-19wt%, ZnO 29-31wt%, Al2O3 2-4wt%, K2CO3 4-6wt%, Na2O 7-9wt%, CaO 2-4wt%, BaO 2-4wt%, MgO 2-4wt%.

[0014] More preferably, the glass matrix comprises the following raw materials in percentage by mass: SiO2 27wt%, B2O3 18wt%, ZnO 30wt%, Al2O3 3wt%, K2CO3 5wt%, Na2O 8wt%, CaO 3wt%, BaO 3wt%, MgO 3wt%.

[0015] Specifically, the sintering time is 20 to 40 minutes.

[0016] Specifically, the calcination time is 120 to 180 minutes.

[0017] Specifically, the CaAlSiN3:Eu 2+ The average particle size of the phosphor is 13 to 15 μm.

[0018] Specifically, the calcination temperature is 1000-1300°C.

[0019] Specifically, the red fluorescent glass film is prepared by the following preparation method:

[0020] S1. SiO2, B2O3, ZnO, Al2O3, K2CO3, Na2O, CaO, BaO, MgO are mixed, calcined at 1000-1300°C, and ground to obtain the glass matrix powder;

[0021] S2. The glass matrix powder, phosphor and organic solvent are mixed to obtain a first fluorescent slurry;

[0022] S3. coating the first fluorescent slurry on a thermally conductive substrate and sintering it at 500-700° C. to obtain the red fluorescent glass film.

[0023] More specifically, in step S1, the calcination time is 120 to 180 minutes.

[0024] More specifically, in step S1 , grinding includes grinding in a mortar and ball milling in a planetary ball mill.

[0025] More specifically, the grinding time in the mortar is 20 to 50 minutes.

[0026] More specifically, the ball milling time in the planetary ball mill is 2 to 6 hours.

[0027] More specifically, in step S2, the organic solvent includes: 1-5 ml of ethyl acetate, 1-4 ml of terpineol, and 0.1-0.8 g of ethyl cellulose.

[0028] More specifically, in step S2, the mixing time is 120 to 180 minutes.

[0029] More specifically, in step S3, the coating method is one of screen printing, spin coating, dip coating, and blade coating.

[0030] Preferably, in step S3, the coating method is screen printing.

[0031] More preferably, the mesh size of the screen used for the screen printing is 40 to 100 meshes.

[0032] Specifically, the thickness of the red fluorescent glass film is 20-80 μm.

[0033] Preferably, the thickness of the red fluorescent glass film is 50-70 μm.

[0034] In the present invention, the thickness of the red fluorescent glass film is controlled by the number of coating times.

[0035] Specifically, the coating times is 1 to 4 times.

[0036] Preferably, the coating times are 1 to 3 times.

[0037] Specifically, the thermally conductive substrate is at least one of aluminum oxide, aluminum nitride, and sapphire.

[0038] A phosphor comprises: the above-mentioned red fluorescent glass film and a heat sink layer.

[0039] Specifically, the method for preparing the phosphor includes: adhering the red fluorescent glass film to the heat sink layer using thermal grease and thermal adhesive.

[0040] Specifically, the heat sink layer is an aluminum heat-conducting heat sink layer.

[0041] More specifically, the aluminum heat-conducting heat sink layer is made of metal aluminum.

[0042] The present invention also protects the use of the above-mentioned red fluorescent glass film or the above-mentioned phosphor in high-power reflective laser display.

[0043] The high power refers to the laser radiation power ≥ 20W / mm 2 .

[0044] Compared with the prior art, the present invention has the following technical effects:

[0045] The present invention selects the components of a specific glass matrix and adjusts the ratio of the components to obtain CaAlSiN3:Eu 2+ A red fluorescent glass film is prepared by mixing phosphor with glass matrix powder at a relatively low sintering temperature. The resulting fluorescent glass film exhibits excellent compactness, effectively improving the external quantum efficiency of the phosphor and significantly enhancing the fluorescence energy conversion efficiency. Furthermore, the resulting red fluorescent glass film exhibits high thermal conductivity, excellent thermal stability, and excellent optical properties, effectively avoiding thermal quenching and improving long-term reliability.

[0046] The present invention combines a red fluorescent glass film with a heat-conducting heat sink to obtain a phosphor. The reflective excitation dynamic fluorescent wheel technology is used to greatly reduce the cumulative time of laser irradiation on the fluorescent conversion material, reducing the risk of thermal quenching and spectrum broadening. 2 Under laser irradiation, the color coordinates of the phosphor provided by the present invention are still stably maintained above 0.68, showing excellent stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 These are photographs of the red fluorescent glass film in Example 1 under irradiation with a 365nm ultraviolet lamp (left) and a blue laser (right).

[0048] Figure 2 For CaAlSiN3:Eu in Example 1 2+Phosphor, glass matrix powder, Al2O3 substrate, CaAlSiN3:Eu 2+ XRD pattern of fluorescent glass film.

[0049] Figure 3 This is an SEM cross-sectional image of the red fluorescent glass film prepared in Example 1.

[0050] Figure 4 This is the X-ray energy spectrum elemental analysis diagram of the red fluorescent glass film prepared in Example 1.

[0051] Figure 5 Graphs showing the steady-state excitation spectrum (excitation wavelength: 450 nm) and emission spectrum of the red fluorescent glass film prepared in Example 1.

[0052] Figure 6 This is a diagram of the quantum yield of the red fluorescent glass film prepared in Example 1.

[0053] Figure 7 Graph showing the thermal diffusivity and thermal conductivity of the red fluorescent glass film prepared in Example 1.

[0054] Figure 8 This is a composite photo of the red fluorescent glass film and aluminum heat sink prepared in Example 1.

[0055] Figure 9 This is the laser spectrum diagram of the phosphor prepared in Example 7 at different power densities.

[0056] Figure 10 This is a power density-luminous flux curve of the phosphor prepared in Example 7.

[0057] Figure 11 The phosphor prepared in Example 7 was 20.34W / mm 2 CIE coordinate diagram of the emission position under blue laser irradiation.

[0058] Figure 12 These are laser spectra of the phosphors prepared in Examples 7 to 12 and Comparative Example 2 at different power densities; wherein, Figure a is Example 10, Figure b is Example 11, Figure c is Example 7, Figure d is Example 12, Figure e is Comparative Example 2, Figure f is Example 8, and Figure g is Example 9. DETAILED DESCRIPTION

[0059] The present invention is further described below with reference to the examples. These examples are intended to illustrate the present invention only and are not intended to limit the scope of the present invention. Experimental methods in the following examples where specific conditions are not specified are generally performed in accordance with conventional conditions in the art or the conditions recommended by the manufacturer; the raw materials and reagents used, unless otherwise specified, are all commercially available from conventional markets. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention fall within the scope of protection claimed in the present invention.

[0060] CaAlSiN3:Eu 2+ Red phosphor: Manufacturer: Youyan Rare Earth, model: HR-655nm, average particle size is 14μm.

[0061] Thermal grease: Manufacturer: NVV, Model: None, thermal conductivity is 8.5W m -1 k -1 .

[0062] Thermal conductive adhesive: AB adhesive: Manufacturer: Deli, Model: No.53574.

[0063] Example 1

[0064] This embodiment provides a red fluorescent glass film (PiGF), the preparation method of which is as follows:

[0065] S1. Raw materials are weighed and proportioned according to the following mass percentages: SiO2 27wt%, B2O3 18wt%, ZnO 30wt%, Al2O3 3wt%, K2CO3 5wt%, Na2O 8wt%, CaO 3wt%, BaO 3wt%, and MgO 3wt%. The raw materials are placed in an agate mortar and ground for 10 minutes until uniform. The raw materials are then transferred to an alumina crucible and placed in a high-temperature muffle furnace and calcined at 1050°C for 120 minutes to obtain molten glass. At this time, the glass melt in the alumina crucible is poured onto a brass module and quenched to obtain glass blocks. The glass blocks are crushed and ground for 30 minutes. The glass powder is then placed in a planetary ball mill and ball-milled for 6 hours, and dried to obtain a glass matrix powder.

[0066] S2, the glass matrix powder obtained in step S1 and CaAlSiN3:Eu 2+ Red phosphor was weighed in an amount of 0.5 g and 0.33 g, respectively, such that the phosphor accounted for 40 wt% of the total mass of the glass matrix and phosphor. The mixture was then ground thoroughly in an agate mortar for 10 minutes. After the mixture was thoroughly mixed, an organic solvent (3 ml of ethyl acetate, 1 ml of terpineol, and 0.25 g of ethyl cellulose) was added to prepare a first fluorescent slurry.

[0067] S3. The red fluorescent glass slurry obtained in step S2 is applied to an alumina substrate with a diameter of 25 mm and a thickness of 2 mm using an 80-mesh screen printing process twice. The coated pre-fluorescent glass film is then dried on a heating plate at 150°C for 3 hours. Finally, the dried pre-fluorescent glass film is sintered in a muffle furnace at 600°C for 30 minutes before removal to obtain a red fluorescent glass film. The phosphor accounts for 40% by weight of the total mass of the glass matrix and phosphor, and the thickness of the fluorescent glass film is 61.11 μm.

[0068] Example 2

[0069] This embodiment provides a red fluorescent glass film (PiGF), the preparation method of which is different from that of embodiment 1 in that the coating is performed once in step S3. The rest is the same as that of embodiment 1.

[0070] Example 3

[0071] This embodiment provides a red fluorescent glass film (PiGF). The preparation method differs from that of Example 1 in that, in step S3, the coating is performed three times, and the phosphor accounts for 30 wt% of the total mass of the glass matrix and phosphor, i.e., the glass matrix powder is 0.5 g and the phosphor is 0.214 g. The remaining methods are the same as those of Example 1.

[0072] Example 4

[0073] This embodiment provides a red fluorescent glass film (PiGF). The preparation method thereof is different from that of Example 1 in that the phosphor accounts for 20 wt % of the total mass of the glass matrix and the phosphor, that is, the glass matrix powder is 0.5 g and the phosphor is 0.125 g.

[0074] Example 5

[0075] This embodiment provides a red fluorescent glass film (PiGF), the preparation method of which is different from that of Example 1 in that the phosphor accounts for 30 wt % of the total mass of the glass matrix and the phosphor, that is, the glass matrix powder is 0.5 g and the phosphor is 0.214 g.

[0076] Example 6

[0077] This embodiment provides a red fluorescent glass film (PiGF). The preparation method thereof is different from that of Example 1 in that the phosphor accounts for 50 wt % of the total mass of the glass matrix and the phosphor, that is, the glass matrix powder is 0.5 g and the phosphor is 0.5 g.

[0078] Comparative Example 1

[0079] This embodiment provides a red fluorescent glass film (PiGF). The preparation method thereof is different from that of Example 1 in that the phosphor accounts for 60 wt % of the total mass of the glass matrix and the phosphor, that is, the glass matrix powder is 0.5 g and the phosphor is 0.75 g.

[0080] Figure 1 The following are luminescence images of the red fluorescent glass film prepared in Example 1 under 365nm ultraviolet light and 450nm blue laser irradiation. As can be seen from the figures, the red fluorescent glass film has good luminescence performance under 365nm ultraviolet light and 450nm blue laser irradiation.

[0081] Figure 2 The XRD diffraction patterns of the red fluorescent glass film (PiGF), the corresponding phosphor, the alumina substrate, and the matrix glass powder prepared in Example 1 are shown in the figure. 2+ The XRD diffraction patterns of the phosphor and the alumina substrate are superimposed, which shows that the phosphor maintains a complete crystal structure in the glass matrix.

[0082] Figure 3 This is a scanning electron microscope cross-sectional image of the fluorescent glass film prepared in Example 1. As can be seen from the figure, the thickness of the red fluorescent glass film is about 61.11 microns. In the cross-sectional image, the fluorescent glass has no pores or defects, which indicates that the fluorescent glass has excellent density. Figure 4 This is an X-ray energy spectrum elemental analysis diagram of the red fluorescent glass film prepared in Example 1. The EDS elemental surface scan confirms that the elements in the glass do not enter the phosphor, thereby enabling the phosphor to maintain a high luminescence performance.

[0083] Figure 5 Graphs 1 and 2 are the steady-state excitation spectrum and emission spectrum of the fluorescent glass film prepared in Example 1. As can be seen from the graph, under 450nm excitation, the fluorescent glass film exhibits a red light emission center with a wavelength of 650nm.

[0084] Figure 6 The quantum yield diagram of the fluorescent glass film prepared in Example 1 shows that the internal quantum efficiency (IQE) of the film is 77.79%, the absorption rate (Abs) is 76.31%, and the external quantum efficiency (EQE) is 59.36%. 2+ The red phosphor has an internal quantum efficiency of 88.58%, an external quantum efficiency of 41.14%, and an absorptivity of 46.44%. This demonstrates that the glass matrix improves the external quantum efficiency and absorptivity of the phosphor, and that the red phosphor glass film exhibits high light conversion efficiency. This is due to the low sintering temperature of the glass matrix powder and the phosphor, which significantly reduces thermal erosion of the phosphor.

[0085] The thermal diffusivity of the fluorescent glass film prepared in Example 1 was measured using the pulse flash method, its specific heat capacity was measured using a differential scanning calorimeter, and the thermal conductivity of the fluorescent glass film was calculated. The thermal conductivity of the film at room temperature can reach 22.06 W m -1 K -1 , demonstrating excellent thermal stability and optical properties, effectively avoiding thermal quenching and improving reliability in long-term use.

[0086] Example 7

[0087] This embodiment provides a phosphor, which combines the red fluorescent glass film of Example 1 with an aluminum thermally conductive heat sink layer, wherein the aluminum thermally conductive heat sink layer is metallic aluminum. The phosphor is prepared as follows: first, a layer of thermally conductive silicone grease is applied to the back surface of the red fluorescent glass film corresponding to the laser irradiation area to improve heat conduction efficiency; then, AB glue is applied to the peripheral area on the back surface of the film to achieve structural fixation and adhesive sealing, wherein the specific application range of the AB glue can be set and adjusted as needed. Then, the red fluorescent glass film is adhered to the aluminum thermally conductive heat sink to obtain the phosphor.

[0088] The testing method is as follows: To test its laser spectral characteristics, the laser's output optical power is first measured using a power meter. Subsequently, the laser spot area is measured using an Ophir-Spiricon beam profiler. Finally, a Labfil integrating sphere test system is used to test the sample in reflection mode and dynamic conditions to obtain its photoluminescence spectrum and corresponding optical parameters such as luminous flux.

[0089] Depend on Figure 9 It can be seen that after the phosphor in Example 7 is excited by 450nm blue light, the red light emission range is 570-800nm, and the emission center is 649nm.

[0090] The luminous flux of the phosphor in Example 7 was further tested as a function of power density, and the results are as follows: Figure 10 As shown in the figure, when the laser power density reaches 20.34W / mm 2 When the power density is 0.05, the luminous flux is 1321.96 lm, and the phosphor still does not experience luminous saturation at this power density, which proves its stability under high laser power density irradiation.

[0091] The color coordinates of the phosphor of Example 7 at different laser power densities are shown in Table 1.

[0092] Table 1

[0093] <![CDATA[Laser power density (W / mm 2 )]]> Color coordinates 1.69 (0.6855,0.3099) 5.08 (0.6837,0.3098) 9.60 (0.6878,0.3121) 14.12 (0.6855,0.3143) 18.30 (0.6825,0.3173) 18.64 (0.6816,0.3182) 20.34 (0.6808,0.3190)

[0094] As shown in Table 1, with the increase of power density, the x color coordinate of the red light emission position is greater than 0.68, which indicates that the phosphor prepared by the present invention has good stability.

[0095] At 20.34W / mm 2 The color coordinates of the phosphor of Example 7 were tested under the power density, and the results were as follows: Figure 11 The CIE color coordinates of its red light emission position are (0.681, 0.319), showing extremely high color purity, which fully meets the strict requirements of laser fluorescent display for red light.

[0096] Examples 8 to 12

[0097] The red fluorescent glass films in Examples 2 to 6 were respectively combined with an aluminum heat-conducting heat sink. The preparation method was the same as that in Example 7. The corresponding parameters of the number of coatings and phosphor content of the red fluorescent glass films are shown in Table 2.

[0098] Comparative Example 2

[0099] This comparative example provides a phosphor, which combines the red fluorescent glass film in comparative example 1 with an aluminum heat-conducting heat sink. The preparation method is the same as that of example 7.

[0100] Table 2

[0101]

[0102]

[0103] Figure 12 The laser spectra of the phosphors prepared in Examples 7 to 12 and Comparative Example 2 at different power densities are shown in Figure a for Example 10, Figure b for Example 11, Figure c for Example 7, Figure d for Example 12, Figure e for Comparative Example 2, Figure f for Example 8, and Figure g for Example 9. The results show that the phosphors prepared in Examples 7 to 12 have a maximum power density of 20.8 W / mm 2 There is no saturation, which proves its stability under high laser power density irradiation. 2 Light saturation occurs when the laser power density is greater than 12.5W / mm 2 When the power density increases, the luminous intensity decreases. This shows that when the phosphor content is too high, the fluorescence performance of the phosphor decreases.

[0104] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A red fluorescent glass film, characterized in that: The red fluorescent glass film includes a glass matrix, CaAlSiN3:Eu 2+ Phosphor and thermally conductive substrate, the glass matrix comprises the following raw materials in percentage by weight: SiO2 20-40wt%, B2O3 10-30wt%, ZnO 30-50wt%, Al2O3 1-5wt%, K2CO3 4-10wt%, Na2O 5-10wt%, CaO 1-4wt%, BaO 2-5wt%, MgO 1-4wt%; The phosphor accounts for 20% to 50wt% of the total mass of the glass matrix and the phosphor. The preparation method of the red fluorescent glass film includes: first calcining the above raw materials to obtain a glass matrix powder, then mixing the glass matrix powder with the phosphor and applying it on a substrate, and sintering to obtain a red fluorescent glass film; the sintering temperature is 500 to 700°C.

2. The red fluorescent glass film according to claim 1, characterized in that: The sintering temperature is 570-620°C.

3. The red fluorescent glass film according to claim 1, characterized in that: The sintering time is 20 to 40 minutes.

4. The red fluorescent glass film according to claim 1, characterized in that: The phosphor powder accounts for 40-50 wt% of the total mass of the glass matrix and the phosphor powder.

5. The red fluorescent glass film according to claim 1, characterized in that: The glass matrix includes the following raw materials in percentage by weight: SiO2 26-28wt%, B2O3 17-19wt%, ZnO 29-31wt%, Al2O3 2-4wt%, K2CO3 4-6wt%, Na2O 7-9wt%, CaO 2-4wt%, BaO 2-4wt%, and MgO 2-4wt%.

6. The red fluorescent glass film according to claim 1, characterized in that: The calcination temperature is 1000-1300°C.

7. The red fluorescent glass film according to claim 1, characterized in that: The thickness of the red fluorescent glass film is 20 to 80 μm.

8. The red fluorescent glass film according to claim 1, characterized in that: The thermally conductive substrate is at least one of aluminum oxide, aluminum nitride, and sapphire.

9. A phosphor, characterized in that The phosphor comprises: the red fluorescent glass film according to any one of claims 1 to 8 and a heat sink layer.

10. Use of the red fluorescent glass film according to any one of claims 1 to 8 or the phosphor according to claim 9 in a high-power reflective laser display.

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